Electrical wire insulated with plasticized polyvinyl chloride (PVC) is used widely for many applications including telephone cords such as those connecting telephone station equipment with wall or floor line junctions and for retractile telephone cords and telephone handsets. It is also used for electrical cords on consumer appliances. In these applications, the cords typically have high visibility coupled with high exposure to wear, staining and environmental degradation. With the increasing demand for cords that are coordinated in color with appliances or interior decor, the aesthetic appearance of the telephone cord is of ever increasing importance.
Notwithstanding the fact that previously used cords are often stained and discolored or have other aesthetic problems associated therewith, the cords nevertheless are suitable for reuse in an electrical sense in that electrical integrity and conductivity have not been affected. It has generally been found to be economical in the telephone industry to refurbish used telephone cords. In order for these telephone cords to be suitable for reinstallation with new phones or replacement equipment in the home or business, the cord must aesthetically appear new. Consequently, substantial quantities of recycled telephone cords must be painted or otherwise coated so as to give the telephone cord as aesthetically new appearance.
To be suitable for this purpose, any paint applied to the cords, must, especially in the case of retractile telephone cords, be flexible and resistant to cracking and peeling. It is also desirable to have a paint formulation which is relatively stain resistant, which can hold sufficient pigment to allow single coat coverage and which dries to a tack-free condition relatively quickly even in fairly humid conditions. Generally, to be suitable formulations should dry to a tack-free condition at relative humidities of 50% in not more than 20 minutes.
Previously, vinyl paint formulations were employed as coatings for the plasticized polyvinyl chloride jackets on telephone cords. These formulations tended to exhibit adhesion problems after a period of time. The adhesion problems were manifested by cracking and peeling of the coating. Furthermore, the stain resistance of the vinyl paints were relatively poor. More recently, the use of urethane paint became widespread for coating telephone cords. While the adhesion problem of the vinyl paints was substantially overcome with the newer urethane formulations, the urethane paint offered only minimal stain resistance. Moreover, processing problems such as reproducibility, the need for multiple coating, and long drying, times were encountered utilizing the urethane coating formulations.
Consequently, it would be extremely advantageous to employ a paint formulation which has good adhesion to the jacketed surface of the telephone cord and which can hold high pigment levels so as to allow one coat coverage while being relatively fast drying and stain resistant.